Rethinking plastic recycling: A comparison between North America and Europe.

In this article, we identify the problem of plastic proliferation, the consequent expansion of plastic waste in our society, the inadequacies of current attempts to recycle plastic, and the urgency to address this problem in the light of the microplastic threat. It details the problems with current efforts to recycle plastic and the particularly poor recycling rates in North America (NA) when compared to certain countries in the European Union (EU). The obstacles to plastic recycling are overlapping economic, physical and regulatory problems spanning fluctuating resale market prices, residue and polymer contamination and offshore export which often circumvents the entire process. The primary differences between the EU and NA are the costs of end-of-life disposal methods with most EU citizens paying much higher prices for both landfilling and Energy from Waste (incineration) costs compared with NA. At the time of writing, some EU states are either restricted from landfilling mixed plastic waste or the cost is significantly greater than in NA ($80 to 125 USD/t vs $55 USD/t). This makes recycling a favourable option in the EU, and, in turn, has led to more industrial processing and innovation, more recycled product uptake, and the structuring of collection and sorting methods that favour cleaner polymer streams. This is a self-re-enforcing cycle and is evident by EU technologies and industries that have emerged to process "problem plastics", such as mixed plastic film wastes, co-polymer films, thermosets, Polystyrene, (PS) Polyvinyl Chloride (PVC), and others. This is in contrast with NA recycling infrastructure, which has been tailored to shipping low-value mixed plastic waste abroad. Circularity is far from complete in any jurisdiction as export of plastic to developing countries is an opaque, but often used disposal method in the EU as it is in NA. Proposed restrictions on off-shore shipping and regulations requiring minimum recycled plastic content in new products will potentially increase plastic recycling by increasing both supply and demand for recycled product.

Pilot-scale, on-site investigation of crushed recycled glass as tertiary filter media for municipal lagoon wastewater treatment.

ABSTRACTGlass recycling is a process that faces many obstacles, especially in the closed-loop context. Waste glass separation and transportation can become quite expensive, turning glass collection for remanufacture unfeasible. For this reason, it is important that alternative markets for waste glass are sought. This study evaluated crushed recycled glass as tertiary media in subsurface pilot-scale filters for on-site municipal wastewater treatment, using control sand media filters. Filters were operated over 128 days at a 24-h hydraulic retention time, treating secondary lagoon effluent from the rural municipality of Dunnottar, Manitoba, Canada. Crushed recycled glass filters removed 92%, 90% and 45% of the total suspended solids (TSS), ammonium nitrogen (NH4+-N) and chemical oxygen demand (COD), respectively. Total suspended solids were removed equally well in sand and crushed recycled glass filters (α = 0.05), whereas NH4+-N and COD reductions were 10% and 21% greater in sand media, respectively. Both sand and crushed recycled glass filters failed to achieve phosphorus (P) discharge guidelines. This study shows that there is potential for crushed recycled glass in wastewater filtration, especially to achieve TSS, COD and NH4+-N removal. Small communities served by waste stabilization ponds could benefit from glass media filters, as waste glass could be diverted from curbside collection and utilized locally to polish municipal lagoon effluent.

Insitu kinetics of human pharmaceutical conjugates and the impact of transformation, deconjugation, and sorption on persistence in wastewater batch bioreactors.

The fate of selected common pharmaceuticals and four of their major conjugates in wastewater batch bioreactors was evaluated to determine how treatment plant parameters such as addition of air, and the presence of waste activated sludge (WAS) could influence the removal of parent compounds and conjugates. Under a realistic hydraulic residence time (HRT) for each treatment sub-process of approximately 2 h, acetaminophen and its sulfate metabolite were both rapidly degraded (>99%). Propranolol was sulfated and concurrently removed. Deconjugation of N-acetylsulfamethoxazole and sulfamethoxazole-glucuronide contributed to increases of the parent sulfamethoxazole. Thyroxine was resistant to degradation, while thyroxine-glucuronide was rapidly deconjugated (>90% in <2 h). In the absence of WAS, sorption to suspended solids was another major removal mechanism for acetaminophen, propranolol, sulfamethoxazole, and thyroxine. However, with WAS, concentrations associated with suspended solids decreased for all analytes within 24 h. These results indicate that both conjugation and back-transformation are compound-specific and dependent on parameters such as HRT, addition of microbial content, and suspended solids levels. Therefore, conjugation-deconjugation processes may strongly influence the speciation of pharmaceuticals and their fate in wastewater treatment plant effluents.